Why are we assuming maliciousness? My best guess that Chrome works this way would be due to combining the sign-in cookies with the general cookies of the browser (e.g. 1 cookie store instead of 2). So when you log in to Google, you log in to Chrome - and vice versa. For non-technical users this is a convenience feature, though for many it does come with privacy concerns. Judging by the comments re cookie clearing, th…
Because based on their history big tech companies (possibly with the exception of Apple) lost any benefits of a doubt.
When they screw up like that I now assume that it's intentional and unless they run into a massive pr disaster or an EU fine of a couple billions they give exactly zero fucks about their users.